Microcomputer simulation of solid‐state ¹³C NMR line shapes affected by quadrupolar nuclei

Abstract

Solid-state I3C NMR spectra of "N-containing compounds obtained under CPMAS conditions often show asymmetric doublets arising from the unaveraged l3C,l4N residual dipolar coupling. A similar result has recently been noticed in deuteriated samples, whose "C resonances showed the combined effect of %,*H dipolar and scalar couplings. A simple approach, easily adaptable to a desk microcomputer, is described for simulating "C line shapes for arbitrary values of quadrupole parameters, C-X (X = I4N, 'H) distances, external field and orientation of the internuclear vector in the axis system where the electric field gradient tensor is diagonal.

Crystal structure, NMR study, dc-conductivity and dielectric relaxation studies of a new compound [C2H10N2]Cd(SCN)2Cl2

“…The dipolar coupling constant D is given by: In our case, a splitting of 104Hz is observed, which corresponds to a value of d = -34.6Hz. These values are in agreement with those reported by Klauss Eichele et al and Olivieri et al [8].…”

“…The splitting between the peaks due to the 14 N m=0 and m= ±1 spin states correspond to -3d, where d is the residual dipolar coupling [8] given by:…”

Phosphorus-31 solid-state nuclear magnetic resonance study of monophosphazenes

“…Note that for compounds 1,2, and 4 the asymmetric doublet had the same relative orientation. This asymmetric doublet has proven useful in elucidating structural characteristics for I 3 c , l 4~ spin pairs (40)(41)(42)(43), and results from a breakdown of the high-field approximation for the I4N in the MAS technique. Under these conditions, magic angle sample spinning no longer completely suppresses the direct dipolar interaction involving 14N and the splitting of the asymmetric doublet depends, among other things, on the orientation and magnitude of the 14N efg tensor (40).…”

Combined variable-temperature and variable-field15N cross-polarization magic angle spinning NMR study of15N,14N residual dipolar coupling in pyrazole derivatives

“…In the case of 2, the situation is the reverse one according to the observed splitting (C88 Hz), and using Eqn (2) Table 2 and those obtained before. 24 We present in Table 4 a combination of and Á values that accounts fairly satisfactorily for the observed splittings while remaining within reasonable boundaries. 1-Aminopyrazole forms in the crystal a structure forming a net of hydrogen bonds.…”